When a very odd but important millionaire was buried at the bottom of the Caribbean Sea, it might have embarrassed Ellery Queen. After all, the millionaire had been the first client of Ellery Queen, Inc. And now the client had joined the mackerels he was deader than. The crew of his yacht was scattered, and there was no autopsy to suggest the ways and means of his death.
However, Ellery Queen, case-hardened and unembarrassed as ever, stepped into the case without batting an eye, bringing along his new partner, Beau Rummell, a tough egg with a yolk of gold. Together they sliced away as mysterious a tangle of events as even Ellery Queen had ever seen. For clues they had one fountain pen covered with tooth marks, and a few additional corpses. The climax delighted Queen. He liked his cases dramatic, especially with a beautiful girl or two thrown in.(Cover)

"The Dragon's Teeth (1939) is an unusual book in the Queen canon. It is certainly not centered on deduction, or the other things that make most of EQ great. Things which one could find disturbing  although the storytelling of the book is much more advanced. EQ tries to create a new hero for the book, and get him involved in romantic adventures. The story succeeds admirably as romantic fiction. If you are going to enjoy it, you just have to accept the book on its own terms, and adjust yourself to its orientation away from EQ's traditions." (Michael E.Grost)

Cadmus Cole was missing at sea. The story is set in N.Y.City, Hollywood and Tarrytown (in the 'Villanoy" room 1726).
A  little while back the Ellery Queen detective agency was founded by Beau Rummell. His father Johnny Rumell was chiefinspector of the narcotics department, and Beau was born in Cherrystreet, N.Y. in 1914. He wore a  moustache and impersonated Ellery on two occasions, once in Hollywood and once in Tarrytown.
Ellery smokes and had appendicitis. He was hospitalized in Adirondacks and was several weeks out.
After this case Ellery immediately starts on a new case.
Richard Queen seldom appears when official business has to be taken care of. Dr.Murphy and dr.Prouty appear as does justice officer Sampson.  NYPD: Velie, Flint and Pigott who knew Beau from childhood.
The story is set between June and Wednesday July 5. Although no year is mentioned we learn that Cole is 66 years old and born in 1873 so it is fair to establish 1939 as the year wherein this story takes place.
No map no challenge to the reader.